Felis ISSN 2398-2950

Actinomyces pyogenes

Synonym(s): Corynebacterium pyogenes

Contributor(s): Melissa Kennedy




  • Genus: Actinomyces (Arcanobacterium).
  • Family: Actinomycetaceae.
  • Order: Actinomycetales.


  • Gk: actino myces- ray fungus; pyogenes- pus-producing.

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Clinical Effects



  • Colonizes the mucous membranes and skin of susceptible species.


  • Reproduces on the mucous membranes of the host by binary fission.


  • Endogenous infection.
  • Bites.

Pathological effects

  • Killed by phagocytes.
  • Man: cell-mediated and humoral allergy - circulating antibody, produced during infection does not confer protection.
  • Specific resistance, if any, is probably cell mediated.
  • Trauma or infection by another agent   →   stimulates latent infection   →   active infection (Actinomycosis Actinomycosis)   →   pyogranulomatous reaction (bacterial colonies with suppuration)   →   surrounding granulation, mononuclear infiltration and fibrosis.

Cattle, sheep and pigs

  • Suppurative mastitis (acute and chronic).
  • Suppurative pneumonia.
  • Septic arthritis.
  • Endometritis.
  • Umbilical infections.
  • Wound infections. Abscesses.
  • Mixed infections withFusobacterium necrophorum.

Bulls and boars

  • Seminal vesiculitis.

Cattle alone

  • Summer mastitis (mixed infection with an anaerobe, eg Peptostreptococcus indolicus).
  • Vegetative endocarditis.

Other Host Effects

  • Present on host's skin and mucous membranes - mouth or orophanynx, secondarily gastrointestinal tract.


Control via animal

  • Drainage of abscesses.

Control via chemotherapies

  • Penicillin G Benzylpenicillin, tetracycline Tetracycline, trimethoprim-sulfamethoxasole Trimethoprim.
    Response to treatment in summer mastitis is disappointing, presumably due to involvement of other bacteria.


  • None.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Lynch M, O'Leary J, Murnaghan D et al (1998) Actinomyces pyogenes septic arthritis in a diabetic farmer. J Infect 37 (1), 71-73 PubMed.
  • Carlson P, Kontiainen S (1994) Evaluation of a commercial kit in the identification of Arcanobacterium hemolyticum and Actinomyces pyogenes. Eur J Clin Microbiol Infect Dis 13 (6), 507-509 PubMed.